“…Therefore, the early diagnosis of malignant gliomas is particularly significant. Presently commonly used imaging methods for glioblastoma diagnosis mainly include positron emission tomography (PET), magnetic resonance imaging (MRI), single-photon-emission computed tomography (SPECT), and near-infrared (NIR) fluorescence imaging. , In recent years, NIR fluorescence imaging, especially in the second biological window (NIR-II FL), has been given much more consideration owing to its strengths of high sensitivity and spatiotemporal resolution, deep penetration, noninvasiveness, and low background noise. − Many kinds of probes have been explored as candidates for NIR-II FL in vivo until now, such as organic molecules, quantum dots, rare-earth fluorescent nanoparticles, and single-walled carbon nanotubes. − Among them, the rare-earth fluorescent nanoparticles are particularly fascinating owing to the exclusive optical properties, including large Stokes, narrow full width at half-maximum, and tunable excitation and emission, as well as good photostability. − Lanthanide oxyfluorides (LnOF, Ln = Y) nanocrystals with the characters of both fluorides and oxides (i.e., low phonon energy, good optical transparency, and chemical stability) exhibit good potential to act as promising probe for NIR-II FL. − Moreover, Nd 3+ ions with relatively large cross sections could serve as good sensitizer for efficient NIR-II emission excited by 808 nm laser through a self-sensitization process. , Therefore, the Nd 3+ -doped YOF fluorescent nanoparticles would be promising candidates for NIR-II FL of orthotopic glioma in vivo.…”